The present invention relates to optical microphone/sensors, and more particularly, to smart optical microphone/sensors.
The term xe2x80x9csmart optical microphone/sensor,xe2x80x9d as used herein, is intended to encompass the sensing and/or measurement performance of the device, including the change of its sensitivity and pre-processing of measurement results during the measurement process, making the measurements more exact, more qualitative and more informative, with less errors and noise.
Optical microphone/sensors are constructed of two dynamic and very fast elements: a source of light and a photo-detector. All of the characteristics of optical microphone sensors, such as sensitivity, noise, frequency band, dynamic range, and so on, depend upon the working conditions of these two elements, which may be changed very quickly during operation, in xe2x80x9creal time.xe2x80x9d
U.S. Pat. No. 5,771,091 and U.S. Pat. No. 6,091,497 disclose optical microphone/sensors including a source of light, producing light used in sensing measurements, which light is sent to a reflective membrane directly from the source or through an optical guide, e.g., an optical fiber or a solid body. Light reflected from the membrane is propagated to a photo-detector directly, or through another light guide. Output signals from the photo-detector are proportional to the intensity of the reflected light.
Smart optical microphone/sensors may change their sensitivity, noise level, amplitude and frequency characteristics, background noise suppression, etc. Such microphone/sensors produce measurements in analog and/or digital form. All of these changes may be made automatically, according to environmental conditions, or according to instructions from an internal and/or external processor. Smart optical microphone/sensors may change their internal characteristics during the measurement process without human intervention; however, known ordinary microphones and sensors do not possess the ability to change their characteristics after production; even more so, during their operation.
It is therefore a broad object of the present invention to provide a smart optical microphone/sensor that may change internal characteristics and measurement according to conditions, results and other needs.
It is a further broad object of the present invention to provide a smart optical microphone/sensor that is able to perform measurements in pulse form in an economical manner, and that may produce output measurements in analog and/or digital form.
According to the present invention, there is therefore provided a smart optical microphone/sensor for sensing distances to a membrane or to a light-reflecting surface, comprising a source of light for illuminating the membrane or light-reflecting surface; a photodetector for receiving light reflected from the membrane or light-reflecting surface and for producing output signals; adjustable means for supplying power to the source of light and a pre-amplifier for amplifying the output signals, whereby the sensitivity of the microphone/sensor can be adjusted.